ABSTRACT

Patternation of a multi-orifice nozzle with an extinction tomography-based optical patternator is reported. Path-integrated transmittances were obtained from a six-orifice nozzle at 1000 Hz. The path-integrated transmittances were deconvoluted using the maximum likelihood estimation method in conjunction with a novel grid scheme. The optical patternator obtains path-integrated extinction measurements at only six view angles due to the limitations in the physical size of the instrument, and the optical arrangement. An older grid scheme would therefore provide an angular resolution of only 30 deg for the deconvolution method. However, a theoretical study with the new grid scheme showed that the angular resolution could be increased significantly by compromising on the radial resolution. This increase of the angular resolution results in a more uniform segment size distribution so that the method is less prone to deconvolution errors. The deconvolution method in conjunction with the new grid scheme was applied to the path-integrated measurements from the six-orifice nozzle. The method successfully resolved the spatial distribution of surface area per unit volume of drops in a horizontal plane within the spray.